We think you should not be worried about the sex of the newly acquired kitten as it is not what determines whether both cats will get along better. Especially if it’s intended to alter them both.

What’s more important, it’s the temperament of both cats, and you should look for a kitten who is nether too shy, too afraid, nor too aggressive or intrusive towards other pets and people.

If possible, visit the intended kitten at his home (no matter if it’s the shelter or the breeder) and check how he interacts with other cats, pets and humans, including you. If the kitten is willing to play with you and other kittens in the litter, and reacts adequately towards different stimuli, you should be fine.

What’s also important, when you come home, do not throw the new kitten in the middle of the room, like saying: “Here I am”. Cats are territorial, so you neither want your resident cat feel threatened about his area, nor you want the new kitten be overwhelmed by the new environment, especially if it’s already claimed.

Instead, make a separate room for the new kitten with its own litter box, water and food trays, bed and everything else (here, read more about bringing a kitten home) and make sure you introduce both cats after the new kitten feels comfortable in his new environment.

But to answer to your initial question, the sex of the kittens is not even close as crucial factor whether they will get along, as their personality.